1. Field of the Invention
The present invention relates to subterranean wells for the production of oil and gas or other fluids. More specifically, the invention relates to an apparatus and method for a providing a single well for simultaneously producing and observing.
2. Description of the Related Art
Monitoring pressure and saturation in a producing reservoir is critical for proper reservoir management, and it is being accomplished throughout the industry in a variety of ways. In offshore fields, wells are drilled from expensive platforms with limited number of drilling slots. Therefore, dedicating a slot for observation only instead of production is costly.
A common practice is to drill a vertical well across multiple zones and perforate the target zone for production and pressure monitoring purposes. At the same time, it is possible to intervene rig-less and run saturation logs across all zones or run production logging across the perforated zone. Inconveniently, this practice has several setbacks. For example, continuous pressure measurement is not possible. Producing the well will cause the pressure immediately around the well bore to drop, and therefore the pressure readings will not be representative of the general area around the well. Getting a representative pressure reading requires shutting-in the well for few days until pressure stabilizes. Shutting-in the well will cause losing potential production and thus revenue.
Another disadvantage of current methods is that production and pressure monitoring have to be in the same reservoir. If production from another zone/reservoir is desired, two reservoirs have to be perforated, isolated with straddle packers and completed with duel completion. Doing so will restrict running logs since the reservoirs will be behind both a tubing and a casing string which will hinder logs from reading the formation. In addition, vertical wells have low production rates compared to horizontal producers so it would be advantageous to have a production well that is horizontal.
From the foregoing, a need has arisen to design a method and apparatus that enables continuous pressure measurement, production and pressure monitoring from separate reservoirs, and production from an accessible horizontal lateral.